need power supply help please

[jigglez rsx]

hello everyone, i purchased the BFG Geforce 7800 GS graphic card and i need a power supply with 400w, 12v current rating of 20v or more, i have a HP Media Center PC 800 and the power supply cant be no longer than 5.5 can anyone help me please????

 

[Trifid]

12v current rating of 20v

You may have some troble there.

This will work well though: http://www.newegg.com/Product/Product.asp?Item=N82E16817104954